Verify downloaded composer phar
Verify downloaded composer phar

The installation of composer (or anything) via curl is prone to
corruption on unreliable networks. This short-term solution mitigates
possible corruption by attempting to load the downloaded phar in PHP. A
better, long-term, solution would be to procure a reliable source for a
packaged deb.

Bug: T86787
Change-Id: I139eafd9a90568f9cd5780ae7264997148cf2530

ankita-kumari/mediawiki-vagrant,HarriAlasi/wiki3dviewer,ankita-kumari/mediawiki-vagrant,HarriAlasi/wiki3dviewer,wikimedia/mediawiki-vagrant,HarriAlasi/wiki3dviewer,stuartbman/mediawiki-vagrant,wikimedia/mediawiki-vagrant,stuartbman/mediawiki-vagrant,ankita-kumari/mediawiki-vagrant,HarriAlasi/wiki3dviewer,stuartbman/mediawiki-vagrant,wikimedia/mediawiki-vagrant,HarriAlasi/wiki3dviewer,stuartbman/mediawiki-vagrant,wikimedia/mediawiki-vagrant,stuartbman/mediawiki-vagrant,wikimedia/mediawiki-vagrant,HarriAlasi/wiki3dviewer,ankita-kumari/mediawiki-vagrant,stuartbman/mediawiki-vagrant,stuartbman/mediawiki-vagrant,ankita-kumari/mediawiki-vagrant,HarriAlasi/wiki3dviewer,ankita-kumari/mediawiki-vagrant,wikimedia/mediawiki-vagrant